Toepassing van weefselkweek en embryogenese bij vermeerdering en veredeling van tulp

In dit rapport worden de resultaten beschreven van twee projecten waarin weekfselkweekmethoden voor vermeerderding en veredeling van tulp zijn onderzocht. Vermeerdering van tulp op het veld gaat erg langzaam waardoor het lang duurt voordat nieuwe cultivars op de markt kunnen worden gebracht. Vermeerdering m.b.v. weefselkweek kan dit aanzienlijk versnellen. Het protocol dat bij aanvang van de twee projecten beschikbaar was, is aanzienlijk verbeterd. In het eerste project werd nagegaan of somatische embryogenese (vorming van embryo's uit niet-geslachtscellen) toepasbaar is voor een sneller vermeerderingssysteem van tulp. Het tweede project draaide om het verbeteren van de vermeedering van tulp in vitro, uitgaande van scheutvorming op bloemstengelplakje

Phase change, bulb growth and dormancy development in lily : manipulation of the propagation cycle by in vitro culture

Contains fulltext : 19304_phaschbug.pdf (publisher's version ) (Open Access)108 p

Propagation of tulip in vitro

A method for propagation of tulip in vitro is reported. Shoots were regenerated from stem explants placed on medium containing 5/iM zeatin and 5ftM a-naphthaleneacetic acid. However, about 90% of the structures formed under these conditions did not contain a meristem and could not be used for propagation. Meristem formation on stem explants was slightly improved by silverthiosulphate and strongly by paclobutrazol or methyljasmonate. The propagation rate under standard conditions was about 1.5 in ten weeks and increased after preculture of shoots in liquid medium.</p

Micropropagation of flower bulbs : Lily and narcissus

For most bulbous crops, artificial (vegetative) propagation methods have been developed, such as scaling (lily), scooping (hyacinth), and chipping (narcissus). Because the speed of these methods is often low, introduction of newly bred cultivars (either produced by conventional breeding or by genetic modification) or of pathogen-free bulbs (produced by meristem culture) requires a long period of time. In tulip, for which no artificial propagation method exists, this can even take 20–25 yr. Micropropagation considerably shortens this period. Furthermore, because of the large number of propagation cycles in the field, conventionally produced bulbs may become easily infected. Micropropagation produces starting material that is completely or predominantly pathogen-free

Phase change in lily bulblets regenerated in vitro

During the development of the lily (Lilium), three phases can be distinguished: the juvenile, the vegetative adult and the flowering phase. Juvenile bulblets sprout with one or a few leaves whereas vegetative adult bulblets sprout with a stem with elongated internodes. The transition to the vegetative adult phase was studied in lily (Lilium x cv. Star Gazer) bulblets regenerating on bulb scale segments in vitro. The phase change was marked by the development of a tunica-corpus structure in the apical meristem which leads to the formation of an actively growing stem primordium. This structure is absent in juvenile bulblets. Juvenile bulblets first developed competence for phase change during a culture period of at least 6 weeks at 25degreesC. Subsequent induction of the phase change occurred during a period of 2 weeks at lower temperature (15degreesC). A major factor influencing phase transition was bulblet weight. Small bulblets never formed a stem whereas large bulblets always formed a stem under inducing conditions. Large bulblets more often formed a stem than small ones but the relation between bulb growth and phase transition was not absolute. A high sucrose concentration, a large explant and a prolonged period for competence development stimulated bulb growth but also phase transition independently of growth. Lowering the concentration of MS-minerals reduced bulb growth but did not affect phase transition. Under these conditions, phase change was correlated with a low phosphorus content